pack fold [removed]c++17 extension) available when building with c++14

Question

The following code contains a fold expression, which afaiu is a c++17 feature:

template  static bool variable_length_or(const T ... v) {         


        

Answer 1

If you don't add something as -ansi -pedantic, to impose a strict conformance to the standard, the compilers are free to adopt some extensions or, in this case, elements of the following standard.

-ansi -pedantic are the options I add for g++ and clang++; other compilers can use different options, obviously.

-- EDIT --

As pointed by Barry (thanks!), -ansi is no more useful and is enough -pedantic.

As pointed by Passer By (thanks!), can be useful the use of -pedantic-error to impose an error, and non only a warning, in case of not strictly conformance.